Hybrid reinforcement design of longitudinal joints for segmental concrete linings

Abstract

AbstractIn mechanized tunneling, the performance of segmental tunnel lining segments is closely bound to the longitudinal joint design. The guiding local effect is partial area strip loading with predominantly plane load distribution. Current normative standards only inadequately cover this case, which leads to an underestimation of the actual bearing capacities and thus offers considerable optimization potential. A hybrid material concept is proposed to improve the joints' performance, which is based on the results of robust combined trusscontinuum topology optimization. It combines high‐performance steel fiber reinforced concrete in the area of load application with conventional materials used for the remaining regions. A relocation of the gasket to the segments' center proves to provide better protection, and a double hinge neck leads to a more efficient load transfer. The effects of these measures on the structural performance are analyzed experimentally and compared against conventional designs. The results show pronounced increases in bearing capacities by using hybrid reinforcements and provide a quantification of optimization based design modifications.